BetterTour installs straight from the web. There's no app store, and it takes about five seconds.
The quickest way: open bettertour.app/get on your phone and follow the one instruction it shows you. It knows which phone you're on.
You have to be in Safari. Chrome and Firefox on iPhone can't add apps to the home screen, because Apple only gives Safari that feature.
Open the site in Chrome and tap Install when it offers. If you don't see it, open the three-dot menu and choose Install app or Add to Home screen.
You're probably in an app's built-in browser. Links opened from Instagram, Facebook, TikTok or LinkedIn stay inside that app, and those browsers can't install anything.
Copy the link, then paste it into Safari or Chrome and try again. Links sent by text message or WhatsApp open in the real browser, so those work fine.
One thing to know on iPhone: the installed app keeps its own separate login from Safari. If you were signed in before installing, sign in once more inside the icon on your home screen and you're set.